Transcript for Syria and the Moment of Truth: President Tries to Rally Support for a Strike

moment of truth about u.S. Military action in syria. All day the president tried to rally support for a u.S. Strike, but at the same time a majority of war weary americans sent word they're cautious. In our new poll, nearly 60 percent oppose a military strike is the u.S. Is going it alone. We have the big story tonight of american leadership at a cross roads. Abc's cheap global affairs correspondent, martha raddatz starts us off right now. Reporter: The president is well aware of how americans feel about involvement in syria but he is determined to carry out a military strike and today the hard sell began. There are how many of you left syria together? Reporter: The president came roaring out of the gate today. Just after 9:00 this morning, the leaders of congress summoned to the white house. At 9:45, even before the meeting starts, the pitch for a strike begins, hitting one of the top concerns head on. It is limited. It does not involve boots on the ground. This is not iraq and this is not afghanistan. Reporter: It's just 90 minutes later. After hearing from the president about evidence the assad regime used chemical weapons against its own people, leaders in both parties say they are on board, that it is time for america to act. I believe my colleagues should support this call for action. Hundreds of children were killed, and we must respond. Reporter:2:30 a.M., The president's national security teams moves to capitol hill to make the strongest pitch yet. Some have tried to suggest that the debate we're having today is about president obama's red line. This debate is about the world's red line. It's about humanity's red line. And it's a red line that anyone with a conscience ought to draw. Reporter: But not everyone was convinced judging from this testee exchange with senator rand paul. If the united states of america doesn't do this, senator, is it more or less likely that assad does it again? You want to answer that question? I don't think it's known. More or less likely that he does it again? It's unknown whether you have the attack. Senator, it's not unknown. Reporter: Away from the capitol, as our poles showed, most of the every day americans speaking to our tell washington cameras were skeptical. I want to tell washington that we should not go to war with syria, we should mind our own business. Obama going in alone would not be the best course of action. For me I think our troops have been through enough. I think that enough is enough. Reporter: Diane, to at the end of the day, the president did make some progress with leadership on the hill, but many memberships remain skeptical about this action, as does the public. This is not going to be easy. We had another milestone today about the syrian people themselves, a number of them fleeing from their homes, for their lives. It's true, diane. Listen to these numbers, there are 2 million syrian refugees. 1.8 million of them became refugees in the last 12 months alone. Every day another 5,000 syrian refugees stream over the boarder into turkey, iraq, jordan, egypt, lebanon. Most of them are women and children. I was recently in the massive camp in jordan and if those camps continue to grow and grow, it is simply unsustainable. These countries like jordan cannot absorb these numbers. As we said on the big story on syria tonight. Thank you.

This transcript has been automatically generated and may not be 100% accurate.

President Assad Fires Back at the United States

More than half a million Syrian Americans living in the United States with family members in Syria.

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